The present invention relates to a semiconductor dynamic quantity sensor, and specifically relates to an adhesive for bonding a sensor chip.
A low melting point glass has been used as an adhesive when a pressure sensor chip, which is a semiconductor dynamic quantity sensor, is bonded onto, for example, a metal diaphragm. The low melting point glass is classified into leaded or unleaded in terms of environmental aspects. Leaded low melting point glass that contains lead oxide has an issue in its use in consideration of recent environmental problems. On the other hand, unleaded low melting point glass requires a bonding temperature of, for example, 400 to 500° C. because it is difficult to lower the melting point without adding lead oxide. Therefore, extra thermal energy is required for bonding, and the sensor chip can be damaged by the high bonding temperature.
Recently, it has been proposed to bond the sensor chip using an organic resin material, which would realize low temperature bonding. However, if an organic resin material such as epoxy resin was used as an adhesive, the deformation due to the setting shrinkage after heating would become so high that e stress would be generated in the sensor chip to vary the sensor output. In addition, if such a sensor would be actually packaged, the stress would decrease due to the creeping phenomenon at the temperature in use. As a result, the sensor output would also vary due to the creeping phenomenon.